FIG. 1 illustrates a conventional piercing mechanism of a bread maker suitable for use in piercing a bread ingredient box 11 so that bread ingredients contained in the bread ingredient box 11 may fall therefrom. The piercing mechanism includes a bottom seat 12 having a hollow rectangular cross section, four support units 13 disposed at four corners of the bottom seat 12, two limiting units 14 respectively disposed on two opposite sides of the bottom seat 12, a top seat 15 spaced apart from the bottom seat 12, and a sawtooth blade 16 disposed on an inner side of the bottom seat 12.
Each support unit 13 includes a support rod 131 extending upward from a respective corner of the bottom seat 12, and a spring 132 sleeved on the support rod 131. Each limiting unit 14 includes two limiting pieces 141 spaced apart in a left-right direction, and a control piece 142 disposed on a housing of the bread maker. Each limiting piece 141 has a limiting hole 143 distal to the other limiting piece 141. The control piece 142 has an arrow-shaped top end removably inserted between the limiting pieces 141.
The top seat 15 has a hollow rectangular cross section, and four corners formed with four holes that are respectively inserted into the support rods 131 of the support units 13 and abutting against top ends of the springs 132 of the support units 13. The top seat 15 further has two pairs of limiting rods 151 respectively and oppositely disposed on two sides of the top seat 15.
When the bread ingredient box 11 is placed on the top seat 15, the top and bottom seats 15, 12 move downward simultaneously, and the control piece 142 is inserted into the bottom seat 12 to push the limiting pieces 141 away from each other. At this time, the limiting rods 151 of the top seat 15 are respectively inserted into the limiting holes 143 of the limiting pieces 141, so that the top seat 15 can move downward relative to the bottom seat 12, and the sawtooth blade 16 can pierce the bread ingredient box 11 disposed on the top seat 15.
However, because the bottom seat 12 is supported only by the control pieces 142 of the limiting units 14, the bottom seat 12 is unstable and is likely to rock. Further, when the conventional piercing mechanism is assembled to or removed from the bread maker, the user's hands are likely to get injured.